The present disclosure relates generally to the field of server computing, and more particularly to managing the energy efficiency of servers providing multi-class computing services.
Server admins have a number of resources available to balance the energy efficiency of a server with the processing capabilities. Server admins may set power management policies to match processing requirements, and the policies in turn may use features such as dynamic voltage and frequency scaling (DVFS) as to raise or lower the voltage and frequency of a server's processor to adjust power consumption. Modern processors may also have low power modes, such as nap or sleep modes, which can be utilized to decrease the energy demand when the server is at idle. Additionally, many modern processors are multi-core processors that can accommodate consolidation of work onto a subset of the cores. This may be called core folding or core parking or other names that convey the consolidation of work. Core folding policy, when enabled, allows the operating system or privileged system software to consolidate the server's work into fewer cores, and unused cores can be turned off or placed in a low power mode to decrease the server's energy demand.
Modern mobile devices, such as smart phones and tablets, have applications with a wide range of Quality of Service (QoS) requirements. Some applications, including online gaming and video streaming, may require an almost instantaneous response. Other applications, like printing services and file downloads, may not be processed by a server for several seconds with little to no impact on the user's experience.